This invention relates generally to the field of flexible containers or bags of the type commonly used in the medical field for storing materials to be delivered to a patient intravenously or parenterally. More particularly, it relates to such a container which is divided into two or more compartments or chambers, each holding a different material, wherein the compartments are separated by a removable barrier, so that the contents of the compartments can be allowed to intermix prior to administration to the patient.
In the medical field, it is often necessary, when administering intravenous medication or parenteral nutrition, to combine two or more materials which must be stored separately. For example, parenteral nutrition frequently makes use of a solution of dextrose and amino acids. Such a solution cannot remain stable for extended periods of time; hence separate storage of the dextrose and the amino acids is necessary. Also, certain drugs that are administered intravenously can only be stored in a dry, powdered form, and must therefore be dissolved in a liquid diluent prior to administration.
While the two (or occasionally more) components of the intravenous or parenteral solution must be separately stored, it is obviously necessary to provide for a quick and convenient mixing of the components in a closed, sterile system just prior to administration. To this end, flexible containers have been devised, in various configurations, with multiple chambers or compartments separated from each other by selectively rupturable or frangible seals or barriers. For example, U.S. Pat. Nos. 4,519,499; 4,465,488; and 4,458,811 disclose multi-chambered containers for medical applications, wherein the chambers are separated by a frangible barrier. Other containers having a frangible or rupturable barrier between two or more compartments are disclosed in the following U.S. Pat. Nos.: 3,175,558; 3,294,227; 3,429,429; 3,462,070; 3,608,709; 3,744,625; 3,756,389; 3,891,138; 3,964,604; 3,950,158; 3,983,994; 4,000,996; 4,226,330; 4,227,614; and 4,402,402.
Prior art containers which utilize a rupturable barrier or seal have several drawbacks. Specifically, in many prior art devices, the action of mechanically breaking or rupturing the barrier or seal must be undertaken with a great deal of care, lest damage result to the container itself. In addition, in some prior art containers of this type, there is a possibility of some fragmentation of the barrier or seal. While in many applications such fragmentation might not present any significant problem, in some applications, such as intravenous infusion, the danger of injury to the patient may be present. As a result, many practitioners in the medical field find the prior art multi-chamber containers difficult or inconvenient to use.
In most, if not all, of the frangible-barrier devices, the strength of the seal or barrier, and therefore the force needed to break it, depend, in substantial part, upon the physical characteristics of the material forming the barrier. Thus, to assure uniformity in the strength of the seal or barrier, its physical specifications must be precisely controlled, thereby adding to the cost of such containers. Moreover, the relatively complex structure of such frangible seals and barriers also adds to the cost of manufacture. Such relative complexity, however, was felt to be unavoidable due to the need to provide good seal integrity while minimizing the chances of inadvertent rupture.
Thus, there has been a long-felt, but as yet unsatisfied, need for a multi-chamber container in which the chambers remain isolated from each other until the mixing of their respective contents is desired, and yet which provides this function with a sealing mechanism that is both economical to manufacture and easy to use without undue concern about either inadvertent inter-chamber leakage or damage to the container itself.